Well tool mounting



March 10, 1959 E. D. HALL ETAL WELL TOOL MOUNTING 2 Sheets-Sheet 1 Filed Aug. '7, 1957 INVENTOR5. 497/?74/ Q #4 BY Jab/7 4 TjORA/EK March 1959 E. D. HALL ETAL 2,877,062

WELL TOOL MOUNTING 2 Sheets-Sheet 2 Filed Aug. 7, 1957 INVENTOR5. E/mer 0. #4

United States Patent WELL TOOL MOUNTING Elmer D. Hall and John A. Hall, Weatherford, Tex.

Application August 7, 1957, Serial No. 676,883

9 Claims. (Cl. 308-4) This invention relates to improvements in well tool mountings for drill pipe or well casing tools and refers more particularly to a mounting construction adaptable for various uses such as mounting drill pipe differential pressure equalizers and protectors or stop collars on oil well casings, tubings or pipe for the purpose of locating and holding them in a desired location or position there on, the mounted tools yet being slidable on the casings or pipes under relatively great application of force thereto.

This application is a continuation-in-part of our application Serial No. 559,185, filed January 16, 1956, entitled Drill Pipe Differential Pressure Equalizer and Protector.

Heretofore it has been conventional practice to attach well tools such as scratchers, centralizers and cement baskets by welding the collars of the tools to the'pipe, or by welding lugs or stops above and below the tools to locate the tools on the pipe and limit their longitudinal movement while permitting their free rotation. The mounting of tools, their limits, or stops by welding is objectionable, not only because of the expense of the labor involved and the necessity of having welding equipment available, but also because it is time consuming and tends to weaken and deteriorate the pipe at and adjacent the weld.

An object, therefore, of the present invention is to provide a well tool mounting construction adaptable to a variety of well tool uses which is simple, inexpensive to manufacture and easy to install by the operators on the job.

Another object is to provide a construction for mounting well tools on either well casing or drill pipe which is strong, rugged and designed to withstand any abuse to which it may be subjected in deep well operations Without slipping or failure.

A further object is to provide a well tool mounting construction which eliminates the necessity of welding operations and insures a satisfactory mounting by the use of steel spring strips which are squeezed between the hollowed out interior surfaces of a collar, band or the like and the cylindrical outersurface of the pipe or casing.

Another object of the invention is to provide a well tool mounting construction for stop collars, differential pressure equalizers and protectors, and the like wherein the collar structure of the mounting itself serves as a protective cover or armoured enclosure over the gripping means.

Another object of this invention is to provide a well tool mounting construction for stop collars, differential pressure equalizers, or the like which is easily mounted either on well casing or drill pipe and which mounting construction permits an outside diameter of the Well tool mounted either relatively small, as generally desired in stop collars, or large, which is generally the case of differential pressure equalizers and protectors.

Yet another object of the invention is to provide a stop collar or other well tool mounting construction 2,877,062 Patented Mar. 10, 1959 whose attachment to the exterior of the casing is such that it will withstand the excessive longitudinal pressures to which it is subjected without displacement but which yet may be displaced by action of the operator along the drill pipe or well casing in certain situations without damaging either the construction or the drill pipe or wellcasing itself.

Another object of the invention is to provide a stop collar or other well tool mounting which may be attached to or mounted on the casing or drill pipe with substan tially any degree of gripping force desired whereby to regulate the amount of longitudinal pressure required to.

displace it along the pipe.

Still another object of the invention is to provide a stop collar assembly or other welbtool mounting construction which is easily positioned or installed at any desired position along the casing string or drill pipe yet is substantially rigidly alfixed to the casing or pipe by gripping forces and pressures applied by the wedging of steel spring strips between the casing or pipe and hollowed out surfaces of the collar or tool mounting.

Other and further objects of the invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant specification and are to be read in conjunction therewith, embodiments of the invention are shown and, in the various views, like numerals are employed to indicate like parts.

Fig. 1 shows a typical joint of drill pipe on which a plurality of drill pipe dilferential pressure equalizers and protectors employing the inventive mounting construction have been mounted.

Fig. 2 is a side view of the inventive mounting construction as applied in a drill pipe differential equalizer and protector with parts cut away and parts in section to better illustrate the inventive construction.

Fig. 3 is a cross-sectional view of the inventive mount ing construction as applied in a drill pipe differential pressure equalizer and protector as in Fig. 2, the equalizer being shown mounted on a pipe section as in Fig. 2, a means for applying sufiicient force to properly mount the equalizer on the pipe also being illustrated.

Fig. 4 shows a modification of the inventive mounting means as applied in a modified form of differential pressure equalizer and protector, the view being a fragmentary one, showing the equalizer portion in section mounted on a drill pipe.

Figs. 5, 6 and 7 are fragmentary perspective views of various types of packing materials operable to be inserted between well tools and the drill pipe or well casing in a modification of the inventive mounting construction.

Fig. 8 is a view of a stop collar employing the inventive mounting construction mounted on a section of well casing, a centralizer being shown mounted relative said stop collar, parts cut away and in section in the view.

Fig. 9 is a view of another modified form of the invem tive mounting construction as applied in a stop collar, the latter shown in an early stage of assembly on a section of well casing.

Fig. 10 is a view subsequent to that of Fig. 9 showing the stop collar of that view assembled.

In our previous application Serial No. 559,185 set forth above, we disclosed a well tool construction desig nated as a drill pipe differential equalizer and protector, which serves both to minimize friction on the drill stem as it passes protrusions or obstructions caused by cornering or bending of the well bore and, also, protects against sticking of the drill pipe under differential pressure. This latter terminology refers to a situation where the contact of the drill stem is against a permeable formation of low basic pressure. The generally higher well bore pressure is found in opposition to this low basic pressure area and the resultant differential pressure tends to force the drill string tightly against the well bof'" wallf f uchf heavy contact greatly increases any alfeady existent friction and, in deep holes or bores especially ,'the amount of strain exerted on the drilling mechaiiis'mat' the top' of the hole is extreme. In addition, the wear that the'drill stem'undergoes when subjected to such conditions tends to cause premature failure of the string, occasional loss of a portion thereof in the hole ajiidtoo frequent replacement of expendable portions of th'string.

Figs. 1-4 illustrate the inventive well tool mounting construction as employed in an equalizer and protector against these above given conditions and will be first described.

Referring then to the drawings, Fig. 1 shows a typical joint o'f 'dr'ill pipe 30 upon which a plurality of the protective'devicesial, referred to hereinafter as equalizers, have been installed." Equalizers 31 are spaced in such a manner" on the'jointthat room is left at the top and bottom thereof for the use of tongs, elevators, slips and other handlingequipment. As is evident from the drawing,"the' outer diameter of the equalizer itself is preferably equal to or slightly greater than the outer diameters of the tool joints of attachment constructions at the ends of the joint of drill pipe 3%. Since in the conventional drill stem or drilling pipe section the tool joints are of greater outer diameter than the outside diameter of the drill stem itself for strength and rigidity, the equalizers must be of a construction to fit around the pipe rather than slip over the tool joints at the ends thereof. In Fig. 1, there are shown four equalizers mounted between the 'two tool joints but three, two, one or more than four could be employed, depending upon the conditions and the effect desired by the operator. The spacing of these equalizers is a matter of choice, as well. This will be evident from the following description of the construction of a typical equalizer which permits its mounting on the pipe at any desired point.

Fig. 2 shows a typical'form of an equalizer mounted on a section" of drill pipe 30. The equalizer comprises a pair. of tube section halves 33 and 34 which form in assembled-relationship atube section. The end edges 35 and 36 of the tube section halves are preferably beveled asshown'. The least internal diameter of the assembled tube section or equalizer is preferably slightly greater than the outer diameter of the pipe 30 on which it is to be-mounted. The outer diameter of the assembled tube section at its greatest is preferably equal to or greater than the outer diameter of the connecting joints of sections of the drillpipe 30. Any desired means may be employed to rigidly fix the tube section halves together relative one another to encircle the drill pipe. The preferred means shown comprises aweld bead 39 which is received in beveled abutting edges 37 and 33 of the tube section halves. An alternative'means of assembling the tube section halves wherein the equalizer would have fiu'sh' unbeveled edges would be to assemble them by butt brazing or hard soldering.

To mount the assembled tube section on the pipe 30 in such manner as to rigidly grip it but yet be slidable thereon under application of the desired degree of force requires the inventive mounting means here described. Cavities 41 are formed in the inside face 42 of each of the tube section halves, each cavity being preferably circumferential of the tube section half it is in and formed so astomatch and continue the opposing cavity in the otherhalf whentheir edges abut. A plurality of spring metal (preferably steel) strips 43 are positioned axially of saidcayities 41, the strips being compressible throughout their widthupon assembly of the halves on the pipe. Br ralgly, the strips 43 are substantially thesame length Whemsuit'able spring steel strips 43 have been compressed upon the drill pipe 30 between it and the equalizer section halves 33 and 34, the result is a device which is slidable upon the drill stem only upon the longitudinal application of pressure or force thereto in the amount of approximately 16,000 pounds per square inch. Such pressure, of course, is far below the strength limitations of the drill pipe itself and, while such pressure is not ordinarily found in the localized areas in which the given equalizer will contact the Well bore, it permits sliding of the equalizer on the, pipe at the Well head if such is desired for any reason. In a first such situation, in case of a twist-off of the pipe near to the equalizer itself, the latter can be shoved down by an overshot. Secondly, in case blowout preventers have to be closed around a joint on which the tool has been installed, the equalizer can be shoved against the tool joint to allow for the maximum working distance of the joint inside the blowout preventers.

The inventive mounting construction comprises the tube section halves. with the. predetermined least inside diameter when assembled, the cavities therein and the spring steel strips as well as the means for joining the halves. The outside form of the metal collar or its outside diameter is germane only to the use to which the device is put (as an equalizer or a stop collar).

Fig. 3 shows an example (essentially schematic) of a means for applying the tube section halves employing the inventive mounting means of Fig. 2 upon a section of drill pipe or drill stem. Frame 44 fits around the pipe and has threaded 45 opening 46 in one arm thereof. Studs 47 and 48 serve to receive locking bar 49. Indentation 50 in the arm opposite that having opening 46, serves to receive one side of a tube section half 33 or 34. Abutting head 51 has. tube section half fitting indentation 52 therein, while shaft 53 mounting head 51 has threads 54 to engage the threaded portion 45 of the opening 46.

To utilize this means of compressing the preferred form of equalizer shown in Fig. 2 upon the pipe, spring strips 43 are positioned within tube section halves 33 and 34 in the cavities 41 thereof and the spring containing sections are fitted around the drill pipe 30 so that the beveled longitudinal edges thereof are flush. Frame 44 is fitted around the unsealed equalizerv and pipe indentation 50 thereof engages one tubesection half. Shaft 53 is rotated so that abutting head 51 engages the other tube section half with indentation 52. Further rotation of shaft 53 (the head 51 does not rotate with the shaft 53) forces the tube section halves toward one another, thus compressing the spring strips 43 on the pipe. The spring strips 43 are preferably of such a widthand strength that compaction thereof upon the pipe requires a longitudinal force of approximately 16,000 pounds per square inch to displace the assembled equalizer axially of the pipe. When the desired degreeof force has been applied, locking bar 49 may be attached over studs.47 and 48 to aid inthe support of the equalizer. on thepipe (the fit of the locking bar on the'studs niay be gauged to serve as a measure of the proper force). Then the tube section halves of the equalizer are welded. together as shown at 39.

Fig. 4 shows a partial sectional view of an equalizer similar to that shown in Fig. 2'with the exception that the spring strips of this modification 55 are upturned as at 56 at the ends thereof and slots 57 are formed in the ends of cavities 58 to receivethe upwardly turned ends of the spring strips. The advantages of .this modification of the spring strips are that the strips are moreeasily positi0nable within the cavities and such positioning may be done originally when the tube section halves are manufactured. The cavities 58 in this modification are deeper than the cavities 41 in theFig. 2 modification, It should be pointed out that this modification of the, mounting means is adaptedto. anyfltool mounting -whichis formedof the desired 'internal' diametenrelative are outside diameter of the pipe and has the cavity formed on the inside surface 'of the component parts. The beveling' of the ends as shown in Fig. 4 and the excess outer diameter of the ring or band enclosing the strips 55 is optional, depending upon whether or not it is desirable to employ the device as a differential pressure equalizer or protector.

Figs. 5, 6 and 7 illustrate difierent forms of metallic sheet to serve as a substitute for the individual spring strips as shown in Figs. 2 and 4. Fig. shows a sheet 59 having corrugations 60 axially thereof, the entire sheet having a curvature so as to properly fit the cavity 41 or cavities 41 of an equalizer section half or halves. Fig. 6 shows another modification of such a spring sheet 61, there being corrugations 62 formed axially thereof with upwardly punched pieces 63 standing away from the corrugations to form the spring elements. Again, the total sheet has a curvature so as to fit it into the cavity of a tube section equalizer half 33 or 34 as 'in Fig. 2 or circumferentially around the pipe to fill both cavities in both halves. Fig. 7 shows another spring sheet modification with the sheet. shown at 64 with counterpunched upward and downward indentations 65 and 66, respectively, therein. Again, the sheet is curved as previously described to fit the cavity of a tube section half cavity 41 as in Fig. 2.

Referring to Figs. 8-10, therein are shown, first, in Fig. 8, a stop collar composed of two half sections analogous to that previously described and, second, in Figs. 9 and 10, a stop collar formed of two rings adapted to be attached transversely thereof. The modification of Fig. 8 will be first described.

Referring to Fig. 8, at 67 is shown a section of well casing of conventional construction. Mounted on the well casing are tube section halves 68 and 69 having beveled longitudinal edges as in the construction of Fig. 2, joined by weld bead 69. The tube section halves have cavities 70 formed on the inner faces or surfaces thereof to receive spring steel strips 71 therein in the same manner as the construction of Fig. 2. The spring steel strips are preferably of substantially the same length as the cavities 70 and said cavities 70 of the tube half sections 68 and 69 preferably match and are circumferential to the stop collar. The least inner diameter of the stop collars, even when assembled on the casing, is preferably slightly greater than the greatest outer diameter of the pipe or casing 67 whereby there may be some play of the pipe therewithin although the spring steel strips 71 grip the tool tightly on the casing.

A centralizer having upper and lower hinged bands 72 and 73 as well as outwardly bowed deflected centralizer bands 74 has been mounted on the casing so the loosely gripping hinged bands 72 and 73 are above and below the collar, respectively. The centralizer thus can move vertically up and down around the stop collar as far as the distance between the bands 72 and 73. The abutment of the top of band 73 and the bottom of band 72 with the assembled tube section limits this movement. It is evident, aside from the difference in outer diameter of the stop collar tube section shown in Fig. 8 and the nonbeveling of its end edges, that this construction is substantially the same as that shown in Fig. 2. The mounting of the stop collar on the casing may be accomplished in the same manner as shown in Fig. 3, utilizing the apparatus therein.

Figs. 9 and 10 show another construction at different stages of assembly. Well casing section 75 has upper internally threaded portion 76 and. lower externally threaded portion 77 whereby to join with like sections of well casing. The outer diameters of the joining sections of the well casing, as distinguished from drill stem sections with their protruding tool joints, generally are not greater than the outer diameter of the casing itself. Thus, the modification of the construction shown in Figs. 9 and 10 may be slid on from either or both ends of the well casing. In Fig. 9, circumferential rings 78 and 79,

having least inner diameters slightly greater than the greatest'outer diameter of the well casing, have been slid onto the well casing 75. Ring sections 78 and 79 have preferably circumferential cavities 80 and 81 formed therein extending out of one end thereof. The open ends of the cavities are positioned so as to be nextone another. The edges of the free ends of the cavities are preferably beveled as at 82 and 83 for a purpose to be described. It should be noted that the cavities 80 and 81, as the cavities 41 in the modification of Fig. 2 and 70 of the Fig. 8 modification, need not be circumferential and limited numbers of spring strips may be received therein.

Spring steel strips 84 having beveled outer end edges 85 and 86 may be wedged into the cavities 81 and 80 by application of longitudinal force of sufiicient magnitude thereto. Various means of positioning springs 84 in the cavities or forcing them in may be employed so only a schematic showing is given in Figs. 9 and 10. At any rate, the beveled edges 82 and 83 of the openings to the cavities will ride over the tapered portions 85 and 86 of the springs with relatively less resistance compared to the resistance encountered once the tapered and beveled portions pass relative one another. The abutting edges of the rings 78 and 79 are preferably beveled as at 87 and 88, respectively, to receive weld bead 89 in Fig. 10, when the rings have been fully assembled and fully enclose the spring strips 84. Of course, butt brazing or hard soldering can be employed to fix flush edges relative one another as in the Fig. 2 modification, if desired. The modification shown in Figs. 9 and 10 would not be adaptable to drill stern use because of the latters oversized tool joints.

Thus it will be seen that the invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. A well tool adaptable for positioning on well casing or drill pipe comprising a pair of metal tube section halves, said halves forming in assembled relationship a tube section, the internal diameter of said assembled tube section being slightly greater than the outer diameter of the pipe to which it is to be fitted, a cavity formed in the inner face of each of said tube section halves to receive resilient means for gripping the assembled halves to the pipe, resilient means for insertion into each of said cavities, the resilient means comprising a plurality of metal spring strips to be inserted lengthwise axially of each of said cavities, and means for connecting the halves together to form the tube section.

2. A well tool as in claim 1 wherein said spring strips have upwardly turned ends thereon.

3. A well tool as in claim 1 wherein said spring strips have upwardly turned ends and said cavities formed in the inner face of each of said tube section halves have slots in the ends of the cavities to receive the tips of the upturned ends of the spring strips.

4. A well tool adaptable for positioning on well casing comprising a pair of metal rings slidable on a well casing and having a least internal diameter greater than the outer diameter of the casing, a cavity formed in the inner face of each ring adjacent one end thereof to receive resilient means for gripping the rings on the casing when the rings are slid together next one another on the casing. and resilient means for insertion into said cavities before the rings are moved toward one another, the resilient A e o l injclaiim where n chf av rin v strip has tapered and edges for easier reception in the cavities of the rings,

6. A well tool as in claim 4 wherein the edges of the rings at the cavities mouths thereof are beveled to permit easier insertion of the endsof the spring strips.

7. A well tool as in claim 4 wherein thespring strips have tapered edges and the edges of the rings at the cavities mouths are beveled whereby to permit easier insertion of the ends of the spring strips in the cavities.

8. A well tool for mounting on drill. pipe or well casing comprising a tube sectionformed of two metal pieces, cavities formed internally in each of said-metal pieces, resilient means for positioning in said cavities, said cavities and resilient means of such form that'when the tube section is assembled the resilient means are gripped between the tube section and the pipe section on which it is mounted so as to resist movement thereof, the resilient means comprising a plurality of individual spring steel strips which are deformed at right angles to the axis of 8 the P pe when the. tube on, is a sembled to, gri the tube'ss tipnen he pipe.

9- A Well testing: mea time on, d ill. n ne Q well casin cemp in a ube, se t on med of w m al. p ece cavities formed internally in, each Of said metal pieces, resilient means for positioning in said cavities, said cavitiesand resilient means of such form that when the tube. section is assembled the resilient means are gripped be.- tween the tube section and the pipe section on which it is mounted so as to resist movement thereof, the resilient means comprising a metal sheet having portions deformed thereof so that, when the sheet is, received between the assembled tube section and the pipe, pressure is, exerted on the metal sheet whereby to grip the, tube section on. the pipe.

References Cited in the file of this patent UNITED STATES PATENTS 

